Why My Link is not being saved?

When I go into my course and then to the unit and add a text with a link to it. It does not always save the link I entered. I have had to go back through all my pages in all the courses for this link and re-enter it. I think it is caching to a link prior. I even delete the old link and at times it will still pull up an old link. Very frustrating to have to back track to make sure link is correct. And even have to enter the link 3 to 4 times for it to take.